Pregnancy is a highly complex physiological state. A woman's entire physiological system is readjusted when pregnant. The heart pumps more blood. The lungs work more efficiently, and the digestive system uses all the food it receives more effectively. The thyroid gland grows fifty percent bigger during pregnancy to meet the demands of increased metabolism. The woman's breasts swell as the milk glands develop. Moreover, because of the enlarging womb, the pregnant woman's lower back develops more curvature, and her body's center of gravity shifts. This postural shift can lead to lumbar lordosis, which is an abnormal forward curvature of the spine. The enlarged uterus also presses on major blood vessels and nerves. Furthermore, a pregnant woman's core body temperature rises. Women who are extremely fit, however, actually have improved body temperature regulation and thus have lower core body temperatures during pregnancy. Also, in pregnancy, the vagina offers a chemically hospitable environment for certain infections, in particular, a yeast-like fungus called Candida Albicans.
Hormonal changes also cause a variety of physiologic opportunities. Two circulating hormones, prolactin and relaxin, loosen and soften ligaments and joints of the body. The blood vessels become relaxed, so blood pools in the legs. There is often a softening of the joint between the pubic bones and sometimes even a separation of these bones. Two sets of ligaments moors the uterus. The round ligaments insert into the groin on the left and right in front of the birth canal. The uterosacral ligaments attach just below the small of the back to each side of the bony structures of the pelvis. Stretching of these ligaments which support the uterus can cause groin pain. Additionally, the hormone progesterone relaxes the ligaments in the back. But unlike muscles which return to their prior shape after being stretched, ligaments remain stretched out.
Due to these anatomical and hormonal changes, exercise within the American College of Obstetricians and Gynecologists (ACOG) guidelines can improve the overall physical and psychological health of the expectant woman, as confirmed by current scientific research. Studies done by J. L. Clapp, III, of Case Western Reserve Medical School showed that aerobically fit women who continued to exercise during pregnancy had a greater stroke volume and VO2 responses at a given heart rate as compared to their sedentary counterparts. Maureen Hatch of Columbia University showed that women who exercise during pregnancy have larger babies who tend to be healthier. Exercise before and during pregnancy apparently plays an important role in promoting the health and well-being of the expectant mother. It will help improve blood circulation, will allow for more efficient digestion, and will provide relief of hemorrhoids and constipation often associated with the later stages of pregnancy. Exercise also improves the consumption and uptake of oxygen. Moreover, exercise has been attributed to aiding labor and delivery as well as shortening postpartum recovery time. In general exercise aids the pregnant woman in feeling better about her changing physique, both physiologically and psychologically. And although pregnancy is not a time to "over-do it", it does not mean that overall physical fitness inevitably declines if the pregnant athlete continues to exercise.
Because of all the physiological changes mentioned above, a pregnant woman needs supporting garments more so than when she is not pregnant. Prior art attempts to address a pregnant woman's changing physiology to help pregnant women exercise with greater comfort have been generally deficient. Moyer's maternity exercise garment, disclosed in U.S. Pat. No. 4,746,318, has a support belt attached to the breast support band, and an abdominal support band attached at the pubis. It is believed that as the expectant mother's belly grows, the breast support of Moyer would appear to pull down off the chest, and the crotch area may feel a cutting sensation as the fabric pulls forward. Moreover, it appears that Moyer's encircling abdominal band would likely press down on the stomach instead of providing the desired relief. Similarly, the torso support garment disclosed by Turner in U.S. Pat. No. 5,094,648 would appear to have the problem of the bra being pulled off the chest as the woman's belly grows. Turner's elastic belt may also ride up onto the stomach during vigorous movement. It is also believed that the maternity garment disclosed by White in U.S. Pat. No. 4,976,653 would inadequately support the back and abdomen when a woman is engaged in weight-bearing exercise. The prior art garments appear to have been binding, uncomfortable, restrictive, and generally inadequate in supporting the weight of the belly during aerobic activity or weight-bearing exercises.
The benefits of exercise during pregnancy are well documented. Unfortunately, currently available maternity athletic wear apparently provide insufficient comfort for the exercise-conscious expectant mothers. In particular, there is a lack of maternity exercise garments that would provide sufficient support for expectant exercisers throughout the full pregnancy term, and especially for joggers who want to continue jogging during the later months of pregnancy.